What humanity does isn't "thought", by and large. Not in any meaningful sense. It's mostly the expression of prejudices combined with associational triggers and repeating what others say.
Part of becoming an effective thinker is recognizing that unpleasant realities need to be acknowledged even when we'd prefer they weren't the case. For people living in this time, in this place, one of those truths is that we're surrounded by blatant stupidity. Even worse, we're blatantly stupid a lot of the time.
Deriving those conclusions from the evidence, and then acknowledging their validity, is one of the basic necessary steps to becoming better. No problem can be (expected to be) solved if we deny its reality.
David Stove's "What Is Wrong With Our Thoughts" is a critique of philosophy that I can only call epic.
The astute reader will of course find themselves objecting to Stove's notion that we should be catologuing every possible way to do philosophy wrong. It's not like there's some originally pure mode of thought, being tainted by only a small library of poisons. It's just that there are exponentially more possible crazy thoughts than sane thoughts, c.f. entropy.
But Stove's list of 39 different classic crazinesses applied to the number three is absolute pure epic gold. (Scroll down about halfway through if you want to jump there directly.)
I especially like #8: "There is an integer between two and four, but it is not three, and its true name and nature are not to be revealed."